Advanced medicine using radiation-generating devices, such as heavy-particle therapy devices, and fundamental testing at accelerator facilities associated therewith require the precise and continuous measurement of the radiation doses and energies of charged particles under high radiation density conditions. In addition thereto, in the event of accidents at nuclear power facilities such as nuclear power plants or the like that make use of nuclear fission, as well as in the reactor environments inside nuclear fusion reactors, the development of which has progressed in recent years, radiation measuring equipment must be installed in high-temperature, high-environmental-load and high-radiation environments in order to take measurements.
The ion beams generated by accelerator facilities and the radiation from nuclear power facilities is generally of high density, and in charged particle-irradiated environments in which the surrounding environment is also at a high temperature, most radiation measuring equipment must be highly reliable.
When taking such measurements, scintillation-type detectors using scintillators are used, and the durability and luminous efficiency of the luminescent material parts that convert radiation to light are extremely important. Scintillators are substances that generate light when radiation impinges thereon, and they are used in positron emission tomography (PET) devices and in industrial applications as well as in the aforementioned radiation measurement applications and in accelerator facilities such as those used in heavy-particle therapy. In current α-ray measuring equipment, materials such as ZnS:Ag,Cu and the like are widely used for the luminous efficiency thereof (see Patent Document 1, Patent Document 2 or Non-Patent Document 1).
However, the scintillator materials such as ZnS:Ag,Cu that are currently used are not recommended for use at a temperature range of approximately 100° C. or higher. For this reason, the properties of the materials are not suitable for radiation measurement in nuclear power facilities, for which they would be expected to be used in high-temperature environments.
Moreover, ZnS:Ag,Cu and the like have the problem that the luminous intensities thereof are significantly degraded by high-density radiation, and thus, they require frequent replacement.